Crop losses in cowpea due to the pod-sucking bugs Riptortus dentipes, Mirperus jaculus, Anoplocnemis curvipes and Nezara viridula

Abstract

The effects of increasing population densities of the cowpea pod-sucking bugs (PSB) Riptortus dentipes, Mirperus jaculus, Anoplocnemis curvipes and Nezara viridula were studied in caged potted cowpea (Vigna unguiculata) plants with infestation levels from 0 (control) to 12 adult bugs per cage. Generally, there was an increase in damage to cowpea (measured as damage to pods and seeds) with increasing in insect density. There was also a highly significant correlation between the number of infesting adult bugs and damage to pods and seeds, and a significant negative correlation between bug numbers and cowpea yield. The results suggest that control measures should be initiated at: 4 bugs (fourth instar and above) per 10 plants for R. dentipes and M. jaculus ; 2 bugs per 10 plants for A. curvipes and 6 bugs per 10 plants for N. viridula at podding stage.